This invention relates to perfluoroalkylalkyl (sulfido- or sulfonyl-) alkylene esters of meta- or parapyromellitates partially esterified with 3-chloro-1,2-propane diol and their compositions and use to impart water and oil repellency to synthetic polyesters, such as polyethylene terephthalate, and to synthetic polyamides, such as nylon 6 or nylon 66, especially fibers of such synthetic materials, and to render the same soil resistant.
Certain fluorinated esters of pyromellitates are known and described in U.S. Pat. Nos. 4,209,610, 4,283,292 and 4,317,736. However, such compounds are devoid, for example, of the sulfido or sulfonyl linking moiety of the present compounds.
In addition, since the soil resistant imparting pyromellitate derivatives are characteristically applied to the fiber at elevated temperatures and the resulting treated fiber is annealed at high temperatures, the thermal stability of such pyromellitate derivatives is of critical importance.
It has now unexpectedly been found that the instant pyromellitate derivatives, particularly those containing sulfone groups, exhibit superior thermal stability.
It is thus an object of the present invention to provide pyromellitate derivatives possessing valuable oil repellant and soil resistant properties.
It is yet a further object of the present invention to provide a method of imparting oil repellant and soil resistant properties on synthetic fibrous substrates by applying an effective oil repellant and soil resistant amount of the instant pyromellitate derivatives to such substrate.
These and other objects of the instant invention are described in the following detailed disclosure and examples.